Farm Water Trough Float Valve GPM Calculator
Calculate the refill rate a livestock water trough needs from herd size and daily consumption, and size the float valve and supply line.
How This Calculation Works
Daily water demand equals the number of animals times their daily consumption in gallons. The refill rate in gallons per minute equals that demand divided by the minutes the valve can run, allowing for peak drinking periods. A float valve must refill faster than the herd drinks.
Field Calibration & Rate Reference Chart
| Surface ac | Avg depth | Acre-feet | Copper lb @ 1 ppm |
|---|---|---|---|
| 0.25 | 4 ft | 1.0 | 2.7 |
| 0.5 | 4 ft | 2.0 | 5.4 |
| 0.5 | 6 ft | 3.0 | 8.2 |
| 1.0 | 4 ft | 4.0 | 10.9 |
| 1.0 | 6 ft | 6.0 | 16.3 |
| 1.5 | 5 ft | 7.5 | 20.4 |
| 2.0 | 5 ft | 10.0 | 27.2 |
| 2.0 | 8 ft | 16.0 | 43.5 |
| 3.0 | 6 ft | 18.0 | 49.0 |
| 5.0 | 6 ft | 30.0 | 81.6 |
Common Questions
How much water does a cow drink per day?
A mature beef cow drinks 10 to 20 gallons per day, more in hot weather or during lactation. Dairy cows drink far more, often 30 to 50 gallons. Use the higher end for peak demand sizing.
What size float valve do I need for a trough?
Size the valve and supply line to refill the trough faster than the herd drinks during peak periods, often 3 to 5 gallons per minute for a moderate herd. A larger valve and line give a faster refill. Match the valve to the supply pressure.
How do I keep a trough from freezing?
Use a heated trough or an insulated, buried supply line, and keep the float valve from freezing. A continuous small flow can help in mild climates. Check the system daily in freezing weather.
How many animals can one trough serve?
It depends on the trough size and refill rate, but a well-sized trough can serve 50 to 100 head if it refills quickly. Provide enough linear drinking space so all animals can drink at once. More troughs reduce competition.